1. Field of the Invention
The invention relates to a beam, that is rectangular in cress-section and in particular is made from a hollow section of an extruded light metal alloy, having at least one undercut groove running parallel to the longitudinal axis of the extruded section in at least one outer face to accommodate an element for connecting a further hollow section. The related cross-sectional faces bearing the longitudinal grooves for the connecting element of a pair of beams are of approximately the same cross-sectional dimensions. Also within the scope of the invention is a construction unit made up of such beams.
2. Discussion of the Prior Art
Known e.g. from EP 0 589 380--for the purpose of arm-like or frame-like beams for installation in machines of all kinds--are hollow sections having a quadratic cross-section and cylindrical opening along the central axis and, parallel to this axis, undercut grooves in each of the outer faces. Hollow sections of this design may be joined together e.g. by means of screws introduced transverse to their longitudinal axis and also to other items such as plates or similar flat elements. These screws are situated towards the ends in a block that can be inserted in the undercut groove. It is also possible to fit together in parallel two of the same hollow sections of quadratic cross-section, thus forming a post or the like construction unit to manufacture display stands for industrial fairs or similar constructions.